Salt Lake City, where a brazen bribery scandal ahead of the 2002 Winter Olympics helped change the way host cities are chosen, was given a second chance on Wednesday when it was named as the site of the 2034 Olympic and Paralympic Winter Games.

But its victory came only after a dramatic decision to revise the host city contract that Salt Lake City and Utah officials had signed. That change would allow the I.O.C. to pull the Games if any effort was made to undermine the authority of the World Anti-Doping Agency, the global regulator of doping in sports.

The sudden adjustment came after several Olympic committee officials, while praising Salt Lake City’s bid before the vote in Paris, expressed anger at efforts by the U.S. authorities to investigate the actions of doping and swimming officials in the case of two dozen elite Chinese swimmers who tested positive for a banned substance before the Tokyo Olympics in 2021.

Those positive tests, revealed by a New York Times investigation this year, have raised questions about WADA’s ability and willingness to police doping in international sports. But it is the federal investigations into the case in the United States, which have already led to at least one subpoena for swimming’s top official, that have rattled top sports and doping officials.

Salt Lake City officials had already agreed to the changes and signed a revised hosting agreement, according to John Coates, the I.O.C.’s top legal official.